4, 4&#39;-bis(triorganosilyl)diphenylalkylamines



United St tes atet 3,308,144 Patented Mar. 7, 1967 Fine This invention relates to new and useful 4,4-bis(triorganosilyl)diphenylalkylamine compounds and to methods of making them.

The compounds of this invention are useful, for example, as antioxidants in high temperature lubricating fluids or as corrosive inhibitors. The compounds of this invention can also be used to prepare quaternium compounds which can be used as corrosive inhibitors, textile treating agents, germicides, etc.

It is an object of the present invention to prepare new 4,4 bis(triorganosilyl)diphenylalkylamine compounds. The compounds of this invention have the general formula wherein R is a monovalent hydrocarbon group free of aliphatic unsaturation containing from 1 to 18 inclusive carbon atoms and R is an alkyl group containing from 1 to 18 inclusive carbon atoms.

The R groups can be any monovalent hydrocarbon radical free of aliphatic unsaturation containing from 1 to 18 carbon atoms. For example, R can be an alkyl group such as a methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, octadecyl, isopropyl, isob'utyl, tertiary butyl, or Z-ethylhexyl group; a cycloalkyl group such as a cyclobutyl, cyclopentyl or cyclohexyl group; an aryl group such as a phenyl, xenyl or naphthyl group; an aralkyl group such as a benzyl or 2-phenylethyl group; or an alkaryl group such as a tolyl, xylyl or mesityl group. Obviously in any one compound each R can be the same or different groups. Particularly preferred compounds are those in which the R groups are phenyl and/ or methyl groups.

The R group can be any alkyl group containing from 1 to 18 carbon atoms. For example, R can be a methyl, ethyl, pro-pyl, isopropyl, butyl, isobutyl, tertiary butyl, amyl, isoamyl, hexyl, octyl, dodecyl, pentadecyl or an octadecyl group. Particularly preferred compounds are those in which R is a methyl or ethyl group.

The compounds of this invention are prepared by first preparing a 4,4dilithiodiphenylalkylamine and then reacting this reagent with a chlorosilane. The first reaction is represented by the equation:

The new compounds of this invention are obtained by reacting the above dilithio derivative with a chlorosilane in accordance with the following equation:

R and R in the formulae in the equations are as defined above.

Diethylether is a suitable solvent for both of the foregoing reactions. The reactions are best conducted at reflux temperature.

The compounds of this invention, in particular the 4,4'-bis(phenyldimethylsilyl)diphenyl N ethylamine; 4,4 bis(diphenylmethylsilyl)diphenyl N ethylamine and the 4,4-bis(diphenylmethylsilyl)diphenyl-N-methylamine, are useful as antioxidants for high temperature lubricating fluids. From .2 to 5 percent by weight (based on the weight of the lubricating fluid) of these compounds can be used to stabilize lubricating fluids. These compounds are especially useful as antioxidants in trimethylolpropane triester fluids.

In order that those skilled in the art can better understand how the present invention can be practiced, the following examples, are given by way of illustration and not by way of limitation. The following examples are exemplary of the best method of the preparation of the compounds of this invention, however, other methods can be employed. In each example, the reaction was carried out in a nitrogen atmosphere.

Example 1 A 500 ml., 3 neck flask was equipped with condenser, stirrer, addition funnel and thermometer. ml. of diethylether and 1.94 g. (0.28 gram-atoms) of lithium wire (cut into 112 pieces) were added. 20 g. (0.056 mol) of 4,4-dibromodiphenyl-N-ethylamine was dissolved in 200 ml. of diethylether and placed in the addition funnel. About 15 ml. of the 4,4-dibromodiphenyl-N- ethylamine ether solution was added to the reaction mixture with vigorous stirring and the reaction mixture heated to reflux. Then 0.25 ml. of l-bromobutane and 0.5 ml. of ethyl bromide were added to the reaction flask to initiate the reaction. The reaction mixture was kept at reflux for two hours. Heating was discontinued and the reaction mixture was kept at reflux by addition of the balance of the 4,4-dibromodiphenyl-N-ethylamine ether solution over a 20 minute period. Upon completion of the addition the reaction mixture became clear and was then stirred for 30 minutes as the pot slowly cooled.

19.1 g. (0.112 mol) of dimethylphenylchlorosilane was dissolved in 50 ml. of diethylether and added over a 12 minute period from the additional funnel. This brought the reaction to reflux again. Upon completion of the addition the reaction was stirred for 7 /2 hours and then filtered through glass wool to remove 0.29 g. (0.042 gram-atoms) of lithium. The filtrate (ether solution) ace-awe was then poured into 500 ml. of an ice solution containing 0.5 mol of NaOH for every one tool of Nit- C1 to separate the organic liquid from the salt formed. The organic layer was separated and dried overnight over anhydrous sodium sulfate. The dried ether solution was filtered through a Buchner funnel and then the solvent was completely removed from the filtrate on a Rinco solvent stripper, leaving a light yellow liquid. Distillation of the residue at 0.90 mm. pressure gave 1.66 g. of a liquid boiling at 64 to 96 C. Further distillation at 0.40 to 0.26 mm. pressure gave 3.44 g. of a liquid boiling at 90 to 184 C. There remained in the flask 17.7 g. of residue which crystallized to give a brown solid having a melting point of 57 to 65 C. 16.3 g. of this solid was recrystallized from hot ethyl alcohol to give 6.65 g. (25.5% yield) of a white solid with a melting point of 63 to 65.5 C. This compound was identified as 4,4-bis phenyldimethylsilyl) diphenyl-N-ethylamine.

Example 2 To one liter, 3-neck flask equipped with condenser, stirrer, addition funnel and thermometer was added 100 ml. of diethylether and 1.94 g. (0.28 gram-atoms) of lithium wire (cut into 100 pieces). A solution of 20 g. (0.056 mol) of 4,4-dibromodiphenyl-N-ethylamine in 300 ml. of diethylether was placed in the addition funnel. A few ml. of the 4,4-dibromodiphenylN-ethylamine ether solution was added to the flask with vigorous stirring, stirring being continued for one hour. Then 0.5 ml. of l-bromobutane was added and the mixture heated to reflux. Next 0.25 ml. of ethyl bromide was added and the refluxing continued for 45 minutes. The remaining amine solution was then added over a 43 minute period 4 drofuran. 19.1 g. (0.056 mol) of 4,4-dibromodiphenyl- N-ntethylamine dissolved in 300 ml. of diethylether and 65 ml. of tetrahydrofuran were added to the flask. Then 26 g. (0.112 mol) of diphenylmethylchlorosilane was added and the reaction left to stir. After stirring 5 minutes the pot temperature rose to approximately C. The reaction was then left to stir overnight. After stirring overnight, no trace of lithium was observed in the reaction mixture.

The reaction mixture was filtered and then the filtrate was poured into 250 ml. of NH Cl-NaOH buffer solution and 250 ml. of water to separate the organic liquid from the salt formed. The organic layer was then separated and the solvent evaporated on a steam bath to :give 34.3 g. of a black oil. This black oil was taken up in boiling absolute alcohol, treated with N-uchar (activated charcoal), and filtered hot. Upon standing overnight, small white crystals (M.P. 1336 C.) began to separate from the filtrate. Recrystallization of these crystals from absolute alcohol gave 1.75 g. (5.4% yield) of a white crystalline solid (MP. 1368 C.). This solid was identified as 4,4-bis(methyldiphenylsilyl)diphenyl-N-methylamine.

Example 4 Example 5 The following products are obtained when the fol-lowing reactants are reacted in accordance with Example 1 and at the same mole ratios as in Example 1.

Reactants Product Dilithio Derivative 01- Silane 1 4,4-dibromodiphenyl-N-isopropylamino. Triphenylchlorosilane 4.4bis tripl1enylsilyl)diphenyl-N-isopropylamine.

4,4- libromodipheuyl-N-liexylamine 'lrimcthylchlorosilane 4,4-bis(trimethylsilyl)diphenyl-N-hexylamiue.

4,4(liliron10diplionyl-N-octylamine. 4,4-dibrontodiphenyl-N-l utylamine 4,4-dibrornodiphenyl-Nethylamine 4,4-dibroinodiphenyl-Nethylamine 4,4-dihromodiphenyl-N-ethylamiue 4,4-dibromodiphenyl-N d0decylamine 4,4-dibromodiphenyl-N-ethylaniine 4,4-dibromodiphenyl-N-octadccylamine Decyldiphenylchlorosilane Cyelohexyldiphenylchlorosilanm Benzyldiphenylchlorosilaue Diphenyloctylchlorosilan e Dipheuyltolylchlorosilaua Diphenyleth ylehlorosilaue Diphenyloctadccylchlorosilane Diphenylpropylchlorosilane.

4,4 bis(decyldiphenylsilyl) diphenyl-N-octylamine.

4 ,4-bis (cyclohexyldiphenylsilyl) diphenyl-N-butylamine. 4,4-l)is (benzyldiphenylsilyl) diphenyl-N-ethylamine. 4,4-bis(diphenyloctylsilyl) diphenyl-N-ethylamine. 4,4-bis(dipheuyltolylsilyl)diphenyl-N-etl1ylan1ine. 4,4-bis (diphenylethylsilyl) diphenyl-N-dodecylamine. 4,4-bis (diphenyloctadeoylsilyl) diphenyl-N-ethylamiue. 4,4-bis (diphenylpropylsilyl) diphenyl-Npctadecylamiue.

to maintain gentle reflux. Stirring Was continued for 30 minutes after the completion of the addition.

A solution of 26 g. (0.112 mol) of diphenylmethylchlorosilane in 100 ml. of diethylether was then added through the addition funnel over a 35 minute period to maintain refiux. The reaction mixture was then stirred for one hour at room temperature and filtered through glass wool to remove 0.40 g. of unreacted lithium. The filtrate was then poured into 500 ml. of NH Cl-NaO'I-I :buffer solution to separate the organic liquid from the :salt formed. The organic layer was separated and dried over anhydrous sodium sulfate. The dried ether solution was filtered and then the solvent removed to obtain 33.1 g. of a light yellow to green oil which solidified upon standing. 8.49 g. of the solid was recrystallized twice from absolute alcohol with 7.91 g. (23.9% yield) of a white solid, M.P. 131-3 C., being obtained. This solid was identified as 4,4-bis(methyldiphenylsilyl)diphenyl-N- ethylamine.

Example 3 That which is claimed is: 1. A compound of the formula wherein R is a monovalent hydrocarbon group free of aliphatic unsaturation containing from 1 to 18 inclusive carbon atoms and R is an alkyl group containing from 1 to 18 inclusive carbon atoms.

2. A compound in accordance with claim 1 wherein at least one of the R groups is a phenyl group with the remainder of the R groups being alkyl groups containing from 1 to 6 inclusive carbon atoms.

3. A compound in accordance with claim 1, wherein R is an ethyl group.

4. 4,4'-bis(phenyldimethylsilyl)diphenyl N ethylamine.

5. 4,4-bis(diphenylmethylsilyl)diphenyl N ethylamine. I

6. 4,4-bis(diphenylmethylsilyl)diphenyl N methyl amine.

(References on following page) References Cited by the Examiner UNITED OTHER REFERENCES Gilman et aL: Jour. American Chem. 800., vol. 71 June 1949, pages 2066-9.

STATES PATENTS Merker 260-4482 M B id 26() 448 2 6 TOBIAS E. LEVOW, Primary Examiner.

Schnabel 260448.2 SAMUEL H. BLECH, HELEN M. MCCARTHY, Erickson et a1. 260-4482 Examiners. Wasserman et a1. 260-448.2 P. F. SHAVER, Assistant Examiner. 

1. A COMPOUND OF THE FORMULA (R)3-SI-(1,4-PHENYLENE)-N(-R'')-(1,4-PHENYLENE)-SI(-R)3 WHEREIN R IS A MONOVALENT HYDROCARBON GROUP FREE OF ALIPHATIC UNSATURATION CONTAINING FROM 1 TO 18 INCLUSIVE CARBON ATOMS AND R'' IS AN ALKYL GROUP CONTAINING FROM 1 TO 18 INCLUSIVE CARBON ATOMS. 